Routing devices within a network, often referred to as routers, maintain routing information that describe available routes through the network. Multi-protocol Label Switching (MPLS) is a mechanism used to engineer traffic patterns within Internet Protocol (IP) networks. By using MPLS, an ingress device, controller or other path computation element can orchestrate the establishment of a dedicated path through a network, i.e., a Label Switched Path (LSP). An LSP defines a distinct path through the network to carry MPLS packets from an ingress device to an egress device. The ingress device for a given LSP affixes a short label associated with that LSP to packets that travel through the network via the LSP. Routers along the path cooperatively perform MPLS operations to forward the MPLS packets along the established path. LSPs may be used for a variety of traffic engineering purposes including bandwidth management.
When a link in the path fails or experiences link flapping (e.g., repeatedly alternating from available to unavailable), an ingress router may implement global repair to protect against the link fault on the path. For example, global repair may provide end-to-end path recovery and/or restoration by calculating a new LSP. In particular, global repair may compute a primary path as a preferred LSP and a secondary path as an alternative LSP in case the primary path fails. For each link failure, global repair may implement Constrained Shortest Path First (CSPF) to configure the preferred LSP and alternative LSP. CSPF may be used to compute a shortest path based on Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS) routing protocols. However, implementing global repair for each instance of a link failure is time intensive and costly.